Delete fanout queues on gracefully shutdown
Delete fanout queues on gracefully shutdown

No reasons to kept fanout queues in case then
a rpc server is gracefully shutdown. The expiration
time of the fanout queue is too long (30 mins), so for
large scales it can accumulate a lot of messages before it be removed

Closes-Bug: 1606213
Change-Id: Ieaa35c454df542042f3a5424d70f87d486693024

ozamiatin/oslo.messaging,ozamiatin/oslo.messaging